Voltammetric behavior of alpha-tocopherol and its determination using surfactant+ethanol+water and surfactant+acetonitrile+water mixed solvent systems

Cyclic voltammograms, at the carbon paste electrode were recorded for alpha-tocopherol dissolved in surfactant+ethanol+water and surfactant+acetonitrile+water mixed solvent systems containing ammonia. The oxidation potential of the vitamin was found to vary with a change in the surfactant, being more positive in cationic surfactants as compared to the anionic or nonionic surfactants. Differential pulse voltammetric technique was utilized for the determination of the vitamin in the above solvent systems. The limit of detection and the linear range varied in different surfactants, the lowest being in the Triton X-100+acetonitrile+water mixtures. Simultaneous determination of alpha-tocopherol and ascorbic acid was carried out. Multivitamin-multimineral pharmaceutical preparations analyzed gave satisfactory results